CVE-2021-43543

Mozilla: Bypass of CSP sandbox directive when embedding

Severity Score

6.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Documents loaded with the CSP sandbox directive could have escaped the sandbox's script restriction by embedding additional content. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

Los documentos cargados con la directiva CSP sandbox podrían escapar de la restricción de scripts del sandbox al insertar contenido adicional. Esta vulnerabilidad afecta a Thunderbird versiones anteriores a 91.4.0, Firefox ESR versiones anteriores a 91.4.0 y Firefox versiones anteriores a 95

Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability. This update upgrades Firefox to version 91.4.0 ESR. Issues addressed include buffer overflow, bypass, denial of service, and spoofing vulnerabilities.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-11-08 CVE Reserved
2021-12-08 CVE Published
2024-08-04 CVE Updated
2025-04-10 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CAPEC

References (11)

URL	Tag	Source
https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html	Mailing List
https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html	Mailing List

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://security.gentoo.org/glsa/202202-03	2022-12-09
https://security.gentoo.org/glsa/202208-14	2022-12-09
https://www.debian.org/security/2021/dsa-5026	2022-12-09
https://www.debian.org/security/2022/dsa-5034	2022-12-09
https://www.mozilla.org/security/advisories/mfsa2021-52	2022-12-09
https://www.mozilla.org/security/advisories/mfsa2021-53	2022-12-09
https://www.mozilla.org/security/advisories/mfsa2021-54	2022-12-09
https://access.redhat.com/security/cve/CVE-2021-43543	2021-12-09
https://bugzilla.redhat.com/show_bug.cgi?id=2030113	2021-12-09

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Mozilla Search vendor "Mozilla"		Firefox Search vendor "Mozilla" for product "Firefox"				< 95.0 Search vendor "Mozilla" for product "Firefox" and version " < 95.0"		-		Affected
Mozilla Search vendor "Mozilla"		Firefox Esr Search vendor "Mozilla" for product "Firefox Esr"				< 91.4.0 Search vendor "Mozilla" for product "Firefox Esr" and version " < 91.4.0"		-		Affected
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				< 91.4.0 Search vendor "Mozilla" for product "Thunderbird" and version " < 91.4.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				11.0 Search vendor "Debian" for product "Debian Linux" and version "11.0"		-		Affected